An efficient implementation of a three-dimensional microcell propagation tool for indoor and outdoor urban environments

2000 ◽  
Vol 49 (2) ◽  
pp. 622-630 ◽  
Author(s):  
W.M. O'Brien ◽  
E.M. Kenny ◽  
P.J. Cullen
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mechiel van Manen ◽  
Léon olde Scholtenhuis ◽  
Hans Voordijk

PurposeThis study aims to empirically validate five propositions about the benefits of three-dimensional (3D) visualizations for the management of subsurface utility projects. Specifically, the authors validate whether benefits from 3D in the literature of building construction project management also apply to subsurface utility projects and map them using a taxonomy of project complexity levels.Design/methodology/approachA multiple case study of three utility construction projects was carried out during which the first author was involved in the daily work practices at a utility contractor. 3D visualizations of existing project models were developed, and design and construction meetings were conducted. Practitioners' interactions with and reflections on these 3D visualizations were noted. Observational data from the three project types were matched with the five propositions to determine where benefits of 3D visualizations manifested themselves.FindingsPractitioners found that 3D visualizations had most merit in crowded urban environments when constructing rigid pipelines. All propositions were validated and evaluated as beneficial in subsurface utility projects of complexity level C3. It is shown that in urban projects with rigid pipelines (project with the highest complexity level), 3D visualization prevents misunderstanding or misinterpretations and increases efficiency of coordination. It is recommended to implement 3D visualization approaches in such complex projectsOriginality/valueThere is only limited evidence on the value 3D visualizations in managing utility projects. This study contributes rich empirical evidence on this value based on a six-month observation period at a subsurface contractor. Their merit was assessed by associating 3D approaches with project complexity levels, which may help utility contractors in strategically implementing 3D applications.


Author(s):  
Ben Gorte ◽  
Sisi Zlatanova

The paper presents a very straightforward and effective algorithm to convert a space partitioning, made up of polyhedral objects, into a 3D block of voxels, which is fully occupied, i.e. in which every voxel has a value. In addition to walls, floors, etc. there are 'air' voxels, which in turn may be distinguished as indoor and outdoor air. The method is a 3D extension of a 2D polygon-to-raster conversion algorithm. The input of the algorithm is a set of non-overlapping, closed polyhedra, which can be nested or touching. The air volume is not necessarily represented explicitly as a polyhedron (it can be treated as 'background', leading to the 'default' voxel value). The approach consists of two stages, the first being object (boundary) based, the second scan-line based. In addition to planar faces, other primitives, such as ellipsoids, can be accommodated in the first stage without affecting the second.


Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 137 ◽  
Author(s):  
Mingrui Liu ◽  
Xiuling Wang

Three-dimensional urban wind field construction plays an important role not only in the analysis of pedestrian levels of comfort but also in the effectiveness of harnessing wind energy in an urban environment. However, it is challenging to accurately simulate urban wind flow due to the complex land use in urban environments. In this study, a three-dimensional numerical model was developed for urban wind flow construction. To obtain an accurate urban wind field, various turbulence models, including the Reynolds stress model (RSM), k-ω shear stress transport (SST), realizable k-ε, and (Re-Normalisation Group (RNG) k-ε models were tested. Simulation results were compared with experimental data in the literature. The RSM model showed promising potential in simulating urban wind flow. The model was then adopted to simulate urban wind flow for Purdue University Northwest, which is located in the Northwest Indiana urban region. Based on the simulation results, the optimal location was identified for urban wind turbine siting.


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